Memory having tunnel barrier and method for writing and reading information to and from this memory

Abstract

A resistive memory comprises a tunnel barrier. The tunnel barrier is in contact with a memory material which has a memory property that can be changed by a write signal. Because of the exponential dependence of the tunnel resistance on the parameters of the tunnel barrier, a change in the memory property has a powerful effect on the tunnel resistance, whereby the information stored in the memory material can be read. A solid electrolyte (ion conductor), for example, is suitable as a memory layer, wherein the ions thereof can be moved relative to the interface with the tunnel barrier by the write signal. The memory layer, however, can also be, for example, a further tunnel barrier, the tunnel resistance of which can be changed by the write signal, for example by displacement of a metal layer present in this tunnel barrier. The invention further provides a method for storing and reading information to and from a memory.

Description

[0001]The invention relates to a memory and to a method for writing and reading information to and from a memory.BACKGROUND OF THE INVENTION[0002]The miniaturization of conventional dynamic random access memories (DRAM) has reached its limits. The information is stored in the form of charges, which decrease as the size of the memory cells decreases. When a bit is represented by fewer than approximately 100-1000 elementary charges, it is technically no longer possible to reliably distinguish between the two states of 0 and 1.[0003]For this reason, research is currently underway into resistive random access memories (RRAM), wherein information is written by way of a change in the resistance of the memory material. These memories promise significantly higher data densities than DRAMs and offer the prospect of a universal memory, which also replaces bulk memory because, in principle, they can be designed to be non-volatile. The magazine Nature Materials, Vol. 6, Issue 12 (2008), provide...

AI Technical Summary

Benefits of technology

The invention is a new type of memory that can be produced with greater reproducibility and lower resistance values compared to previous memories. This is because changes to the tunnel barrier, which is the main component of the memory, are not necessary. The design and production of the tunnel barrier have already been optimized for other applications. The memory has been found to have a powerful effect on tunnel resistance, which is determined by small changes in the conduction band edge and spatial division of the tunnel barrier. These changes can be induced by a small write signal carrying information. By measuring these changes accurately, the memory can store information without discretization, resulting in a better signal-to-noise ratio. The memory cells can be tolerated to manufacturing differences to a certain extent, as the changes in resistance caused by the stored information are much larger than any differences in the tunnel barrier.

Problems solved by technology

The disadvantage of existing resistive memories is that the resistance values thereof vary within a wide range, and the production thereof is difficult to reproduce.

As a result, it has not yet been possible to commercialize the technology, even though the technology has been known and under discussion since the 1960s.

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